Avelumab Plus Talazoparib in Patients With <i>BRCA1/2</i>- or <i>ATM</i>-Altered Advanced Solid Tumors
Authors: Alison M. Schram, Nicoletta Colombo, Edward Arrowsmith, Vivek Narayan, Kan Yonemori, Giovanni Scambia, Amelia Zelnak, Todd M. Bauer, Ning Jin, Susanna V. Ulahannan, Marco Colleoni, Philippe Aftimos, Mark T. A. Donoghue, Ezra Rosen, Vasilisa A. Rudneva, Melinda L. Telli, Susan M. Domchek, Matthew D. Galsky, Margaret Hoyle, Colombe Chappey, Ross Stewart, John A. Blake-Haskins, Timothy A. Yap
Journal: JAMA Oncology (2022)

Importance Nonclinical studies suggest that the combination of poly(ADP-ribose) polymerase and programmed cell death 1/programmed cell death–ligand 1 inhibitors has enhanced antitumor activity; however, the patient populations that may benefit from this combination have not been identified. Objective To evaluate whether the combination of avelumab and talazoparib is effective in patients with pathogenic BRCA1/2 or ATM alterations, regardless of tumor type. Design, Setting, and Participants In this pan-cancer tumor-agnostic phase 2b nonrandomized controlled trial, patients with advanced BRCA1/2- altered or ATM -altered solid tumors were enrolled into 2 respective parallel cohorts. The study was conducted from July 2, 2018, to April 12, 2020, at 42 institutions in 9 countries. Interventions Patients received 800 mg of avelumab every 2 weeks and 1 mg of talazoparib once daily. Main Outcomes and Measures The primary end point was confirmed objective response (OR) per RECIST 1.1 by blinded independent central review. Results A total of 200 patients (median [range] age, 59.0 [26.0-89.0] years; 132 [66.0%] women; 15 [7.5%] Asian, 11 [5.5%] African American, and 154 [77.0%] White participants) were enrolled: 159 (79.5%) in the BRCA1/2 cohort and 41 (20.5%) in the ATM cohort. The confirmed OR rate was 26.4% (42 patients, including 9 complete responses [5.7%]) in the BRCA1/2 cohort and 4.9% (2 patients) in the ATM cohort. In the BRCA1/2 cohort, responses were more frequent (OR rate, 30.3%; 95% CI, 22.2%-39.3%, including 8 complete responses [6.7%]) and more durable (median duration of response: 10.9 months [95% CI, 6.2 months to not estimable]) in tumor types associated with increased heritable cancer risk (ie, BRCA1/2 -associated cancer types, such as ovarian, breast, prostate, and pancreatic cancers) and in uterine leiomyosarcoma (objective response in 3 of 3 patients and with ongoing responses greater than 24 months) compared with non– BRCA -associated cancer types. Responses in the BRCA1/2 cohort were numerically higher for patients with tumor mutational burden of 10 or more mutations per megabase (mut/Mb) vs less than 10 mut/Mb. The combination was well tolerated, with no new safety signals identified. Conclusions and Relevance In this phase 2b nonrandomized controlled trial, neither the BRCA1/2 nor ATM cohort met the prespecified OR rate of 40%. Antitumor activity for the combination of avelumab and talazoparib in patients with BRCA1/2 alterations was observed in some patients with BRCA1/2 -associated tumor types and uterine leiomyosarcoma; benefit was minimal in non– BRCA -associated cancer types. Trial Registration ClinicalTrials.gov Identifier: NCT03565991